Do different cassette lengths play back at different speeds?

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Will25

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I've been using SA90s and I recently got some SA60s but playback seems to be slower...is this normal or is there something wrong with my cassette deck? Thanks
 
^ Tape speed is controlled by the capstan and roller- the take-up reel has to "wait" on the speed the capstan/roller is turning. I'd do a test- record the same 29-min. program (long, so as to miminize the effect of human error) on each type of tape and check the program duration on each.
 
Will25 said:
I've been using SA90s and I recently got some SA60s but playback seems to be slower...is this normal or is there something wrong with my cassette deck? Thanks
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Could be a machine fault.

Make sure you fast forward and rewind the cassettes before use to minimise any stickymess and make sure the heads and capstan are cleaned with isopropyl alcohol.

And, yes, the speed is the same - C90s use a tape one-third thinner than a C60 (and a C120 is half the thickness of a C60 so as to get twice the length in the same size cassette).
 
Hmm recorded a 15 min program on a SA60, played it back and it stopped at 14.29 on a stopwatch...what does this mean?
 
Will25 said:
Hmm recorded a 15 min program on a SA60, played it back and it stopped at 14.29 on a stopwatch...what does this mean?
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Your playback speed is faster than your record speed by 3.4%.

But to be sure you did the test right, are you sure the tape didn't stop before the 15-minute program finished recording? That is, do you know for sure the tape was still spinning past the 14.29 minute mark during recording. And by, "Stopped" do you mean the tape physically reached the end or you hear the music end and there's more tape left?

If using a portastudio your speed may be doubled to 3-3/4 ips, depending on model. In that case a 60-minute cassette will give you about 15 minutes of record time in one direction. What model cassette deck are you using?

Also check your stop watch with your computer clock and a second clock to be sure it's consistent.

And yes, 60 and 90 minute cassettes should perform the same. If anything, longer cassettes may drag, but on a properly working deck you shouldn't encounter that until tape is 100+ minutes long. Most often seen with 120 and above.
 
Thanks Beck, I haven't had chance to re-time it, I'll have another go tomorrow morning. this playback difference, should I get it 'normalised'? Or are most cassette decks slightly off?
 
Back in the days when my studio had 4 cassette decks, to check the speed of each machine, I recorded an A tone (440hz) onto a tape from a cassette machine that I thought would be the right speed (I sussed this out by playing along to record music on an actual cassette album and my instrument was in tune, concert pitch).

I then played the tape with the 440 tone in each of the other cassette machines and check the tone with a tuner, if the tone was sharp the machine was running fast, if the machine was flat it was running slow. In fact 3 out of 4 were on pitch and the 4th machine was out slightly, I adjusted the motor speed until it was correct.

What I suggest you do is to record a 440 tone on your machine, then play it back and see if it's playing back at the same pitch.

Oh yah, why would I have had 4 cassette decks? well before the days of computers, cd burners and mp3 players, at thew end of a session the band wanted some copies to take home for a listen, and so I did not have sit there recording lots of copies I was set up to do 4 copies at once.

Alan.
 
Will25 said:
That's a good idea Alan, about to try it. is changing the motor speed difficult?

here's something I've recorded for demonstration....to me it sounds slightly flat and warbly...so frustrating!
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The motor speed adjustment is usually a circuit board mounted screwdriver type potentiometer, I don't know where it is exactly on your machine but it should be near the motor. There are also some motors that have the adjustment screw in the back of the motor itself so have a look there. When trying the adjustment, take note of the original position in case you need to put it back where it was.

It also sound like the machine may have a bad belt in it or a worn capstan wheel. The capstan wheel is what makes contact with the tape to drive it along. It could also be a dirty capstan wheel but be careful what you clean it with as the rubber may be fragile. Read the "What to use for cleaning pinch rollers and other rubber items" on Terry's rubber rollers site, you have to scroll down the page.

Also make sure the heads are clean, if they have oxide on them this can lead to extra drag on the tape and cause speed problems. Clean with a cotton bud and Isopropyl alcohol.

Cheers

Alan.
 
Thanks for your help. I regularly clean the heads so I don't think it's them. I'll see if there's anyone around who can repair it...I can order a new belt but I'm in England so it's going to take some time. :(
 
Do Cassette tapes play at the same speed

Hi, I'm a new member so forgive me if I make any errors in contacts.
Compact Cassette Speed.
Cassette decks should all have the same speed, various tapes may last longer then others as the reference implies, ie. 60, 90, 120 etc. as the length of the tape is longer.
It does sound like a problem with the machine itself though, firstly, have you carried out a tape-head cleaning exercise? - including all the tape guides? having dirty guides will increase the friction to the tape, thereby slowing it slightly if there is any stretching on the drive belt.
A second point is, what machine is it? as drive belts over time can expand making them more likely to slip when in use, they can be replaced but you have to be quite careful when disassembling the transport mechanism to access the belt(s)
 
I've giving it a full clean so I think it must be the belt...just ordered one from ebay! It's a Tascam 488 mk II, I've never looked inside it before but surely changing the belt can't be that difficult? I've got a service manual for a bit of guidance.

In regards to the speed - so I record a 440Hz tone (from a tuning fork probably) on a cassette and then play it back...would it work to run the headphone out to a digital tuner to measure the pitch?
 
Will25 said:
In regards to the speed - so I record a 440Hz tone (from a tuning fork probably) on a cassette and then play it back...would it work to run the headphone out to a digital tuner to measure the pitch?
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You can try the headphone out it will probably work, or a line out plugged into the tuner will work.

If when playing back the tuner deviates up and down, this will indicate that there is a drive problem, slipping belt or bad pinch roller.

Alan.
 
thanks Alan, about to fit the new belt today so I'll give that a whirl afterwards.

I'm just thinking, a different playback speed would mean that my multi-tracks will all be slightly out of pitch with each other, right?
 
Will25 said:
thanks Alan, about to fit the new belt today so I'll give that a whirl afterwards.

I'm just thinking, a different playback speed would mean that my multi-tracks will all be slightly out of pitch with each other, right?
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If you swap tapes between machines.
 
Ahhhh yeah of course, because it will still record at the same speed on each track :rolleyes: haha thanks
 
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